A root directory is the top-most directory in a computer file system hierarchy. In some computer systems, the root directory contains specific subdirectories for applications, libraries and configuration data. For example, in Unix-like operating systems the root directory is usually denoted with a single ‘/’. Some examples of specific subdirectories in Unix-like operating systems include ‘/bin’, ‘/etc’ and ‘/lib’. In the Windows® operating system, each drive is represented by a letter and a root directory for the drive (e.g. ‘C:\’). The root directory on the Windows® system drive usually includes specific subdirectories such as ‘C:\Program Files’ and ‘C:\Windows’.
Sometimes users of a computer system can access the root directory. Many operating systems, however, may limit users' ability to make changes to the root directory and important subdirectories. For example, a non-administrative user may not be able to delete files or subdirectories in the root directory, since doing so may destabilize the computer system or make the computer system insecure.